Grayscale calibration and quality assurance of diagnostic monitors in a PACS system

Abstract

The aim of this study was to calibrate monitors used in soft-copy review of diagnostic images in a pictures archiving and communication system (PACS) and to assess critical quality assurance (QA) parameters through appropriate checks. Barco [cathode ray tube (CRT) and liquid crystal display (LCD)] and EIZO (LCD) monitors were evaluated. Calibration and QA controls were carried out during acceptance tests on the systems and every 6 months according to the Task Group 18 (TG18) report by the American Association of Physicists in Medicine (AAPM). The parameters in question include: maximum luminance, contrast ratio, luminance response, spatial resolution and angular response. A subjective evaluation of image quality was also conducted by a number of radiologists. Barco medical monitors' results were well within tolerances, with significant parameters persisting over time. EIZO nonmedical monitors showed rapid performance deterioration below the minimum requirements. Calibration had to be repeated only in a few cases. Radiologists' evaluations showed that monitor quality is equal to or even better than that of conventional films. Medical monitors turned out to be fully adequate to the task. Periodic QA tests are, however, absolutely necessary to ensure constant quality levels.